84 SYNOPSIS OF THE FLORA OF COLORADO. 



TETRAD YMiA 1 CANESCENS, DC., var. INERMIS, Gr. (T. inermis, Kutt.) 

 Shrubby, much branched, l-2 high, silvery-canescent, unarmed; 

 leaves thiekish, short, 6"-9" long, l"-2" wide, densely tomentpse, acute 

 but scarcely mucronate; axillary fascicles of smaller leaves none; heads 

 corymbose-clustered; in volucral scales 2 // -4 // long, four, oblong, obtuse, 

 carinate; florets 4; achenia sparingly villous with short, soft hairs, soon 

 becoming nearly smooth. North Park, Hayden. Upper Arkansas, Por- 

 ter. Arkansas River, Coulter. 



TETRADYMIA GLABRATA, T. & G. Pacif. R. R. Rep., 2, p. 122, t. 5. 

 Shrubby, divaricately branched, unarmed; young branchlets and foliage 

 loosely clothed with white floccose wool which is soon deciduous; leaves 

 subulate or acerose, rather fleshy, primary ones erect, not spinesceut, 

 3"-o" long, " wide, linear-subulate, mucronate, producing the next year 

 from their axils shorter, obtuse, ericoid leaves ; heads corymbose ; 

 scales of the involucre 4, white-pubescent or glabrate, about 4" long; 

 florets 4; achenia villous, the hairs much shorter than the pappus. 

 Wet Mountain Valley, Brandegee. 



CIRSIUM UNDULATUM, Spreng. Near Denver, Dr. Smith. Along the 

 Platte, and also a form with yellowish flowers, Coulter. 

 . CIRSIUM VIRGINIANUM, MX. Wet Mountain Valley, Brandegee. 

 Along the Platte, Coulter. 



CIRSIUM FOLIOSUM, DC., (C. edule, Nutt.) Stem erect, stout, striate, 

 somewhat woolly, branched toward the top ; leaves loosely webby on 

 both surfaces, elongated, G'-ll' long, not over 1' wide, irregularly sinu- 

 ate-toothed, teeth triangular, and the veins ending in strong stramineous 

 spines ; heads large, glomerate in the axils of the uppermost leaves, or 

 peduncled ; involucral scales linear-lanceolate, appressed, spine-tipped, 

 arachnoid-tomentose. Near Denver, Dr. Smith. Hall cJ& Harbour, 330 

 and 341. Weston's Pass and Sierra Madre Range, Coulter. 



CIRSIUM DRUMMONDII, T. & G. Stemless or with simple stems, l-2 

 high, sparsely hairy ; leaves green and smooth above, paler and slightly 

 webby beneath, radical ones oblanceolate or spatulate, primary ones 

 entire, with ciliate-spinulose margins, later ones and the stem-leaves 

 pinnately toothed or incised, often doubly so, and spiny with weak 

 slender prickles; heads 1-4, sessile or short- stalked, surrounded either 

 by the radical leaves or by a circle of leaves at the top of the stem : 

 involucres glabrous, or with the scales softly ciliate on the margins ; 

 -scales triangular-lanceolate, appressed, tipped with weak prickles ; 

 flowers red or purplish. - 



(a.) Caulescent form. Hall & Harbour, 343. (b.) Acaulescent form. 

 Hall & Harbour, 339. Sierra Madre Range, Coulter. 



CIRSIUM ERIOCEPHALUM, Gr. Proc. Acad. Phil., March, 1863, p. 69. 

 Stein l-2 high, simple, leafy, deciduously arachnoid-tomeiitose ; leaves 

 nearly smooth above, paler and webby beneath, far decurrent, linear or 

 dblong-linear, pinnatitid, with very numerous, crowded, short, very spiny 

 lobes; heads several, sessile, in a dense terminal cluster, iuvolucrate 

 with very spiny foliaceous bracts which pass gradually into spinulose- 

 ciliate, spine-tipped involucral scales, which are clothed with a finely 



1 TETRAD YMIA, DC. Heads 4-nowered, (in one species 5-9-flowered;) the flowers all 

 tubular, perfect and fertile ; the corollas funnel-form with a long slender tube, deeply 

 5-lobed, the linear lobes slightly recurved. Involucre of 4 (rarely 5-6) sub-equal con- 

 cave-cariuate, rigid, oblong, scales. Receptacle very small, naked. Anthers linear, 

 exserted. Branches of the style linear, with very short, ovate, obtuse, pubescent append- 

 ages. Achenia oblong-linear, villous or glabrate. Pappus copious, of very fine, un- 

 equal, capillary, denticulate filaments as long as the tube of the corolla. 



